This grenade used the WW2 designation M38.
The post-ww2 version of it had some changes and the name was altered to M38/46.
It looks like the RB M50 that replaced this defensive grenade.

Total length : 99mm
Diameter : 55mm
Weight : 450gram
Filling : 90gram TNT
Fuze delay : 5-6 seconds

Photos © Josip.